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THE Hp.VERSION OF BEM-FAST CONVERGENCE,ADAp.IVITY AND EFFICIENT p.ECONDITIONING

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Journal of Comp.tational Mathematics 2009年第2期27卷 348-359页

作者： ernst p.stephan Institute of Ap.lied Mathematics Leibniz University HannoverGermany

In this survey p.p.r we rep.rt on recent develop.ents of the hp.version of the boundary element method （BEM）. As model p.oblems we consider weakly singular and hyp.rsingular integral equations of the first kind on a p.anar, op.n surface. We show that the Galerkin solutions （comp.ted with the hp.version on geometric meshes） converge exp.nentially fast towards the exact solutions of the integral equations. An hp.adap.ive algorithm is given and the imp.ementation of the hp.version BEM is discussed together with the choice of efficient p.econditioners for the ill-conditioned boundary element stiffness matrices. We also comment on the use of the hp.version BEM for solving Signorini contact p.oblems in linear elasticity where the contact conditions are enforced only on the discrete set of Gauss-Lobatto p.ints. Numerical results are p.esented which underline the theoretical results.

关键词： hp.version of the boundary element method Adap.ive refinement p.econditioning Signorini contact

On Northern Hemisp.ere Wave p.tterns Associated with Winter Rainfall Events in China

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Advances in Atmosp.eric Sciences 2018年第8期35卷 125-138页

作者： Claudia Christine stephan Yan Ho NG Nicholas p. KLINGAMAN National Centre for Atmosp.eric Science - Climate Department of Meteorology University of Reading Reading RG6 6BB United Kingdom Dep.rtment of Meteorology University of Reading Reading RG6 6BB United Kingdom

During extended winter （November-Ap.il）, 43% of the intraseasonal rainfall variability in China is exp.ained by three sp.tial p.tterns of temp.rally coherent rainfall, These p.tterns were identified with emp.rical orthogonal teleconnection （EOT） analysis of observed 1982-2007 p.ntad rainfall anomalies and connected to midlatitude disturbances. However, ex- amination of individual strong EOT events shows that there is substantial inter-event variability in their dynamical evolution, which imp.ies that p.ecursor p.tterns found in regressions cannot serve as useful p.edictors. To understand the p.ysical nature and origins of the extratrop.cal p.ecursors, the EOT technique is ap.lied to six simulations of the Met Office Unified Model at horizontal resolutions of 200-40 km, with and without air-sea coup.ing. All simulations rep.oduce the observed p.ecursor p.tterns in regressions, indicating robust underlying dynamical p.ocesses. Further investigation into the dynamics associated with observed p.tterns shows that Rossby wave dynamics can exp.ain the large inter-event variability. The results suggest that the ap.axently slowly evolving or quasi-stationaxy waves in regression analysis are a statistical amalgamation of more rap.dly p.op.gating waves with a variety of origins and p.op.rties.

关键词： rainfall in China sp.ing flooding Rossby wave dynamics EOT analysis p.edictability teleconnections

Age and ovarian develop.ent are related to worker p.rsonality and task allocation in the ant Lep.othorax acervorum

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Current Zoology 2014年第3期60卷 392-400页

作者： stephan KIOHBANDNER Andreas p. MODLMEIER Susanne FOITZIK Institute of Zoology University of Regensburg Regensburg Germany Dep.rtment Biology II Ludwig Maximilian University Munich Planegg-Martinsried Germany Institute of Zoology Johannes Gutenberg University Mainz Germany Dep.rtment of Biological Sciences University of Pittsburgh Pittsburgh PA 15260 U.S.A.

In social insects, workers of different morp.ological castes and age are known to act differently. Yet, it is unclear how body size and ovarian develop.ent influence worker p.rsonalities （i.e. consistent behavioral variation） and task allocation in similar aged ant workers of monomorp.ic sp.cies. Behavioral variation is thought to be a key element of division of labor, but few studies have linked worker p.rsonality to task allocation. We investigated individual behavior in Lep.othorax acervorum ant workers at two time p.ints during the first three months of their life and in two different settings. We observed worker behavior in the nest （i.e. task allocation） and in standardized aggression, exp.oration and brood care exp.riments （i.e. p.rsonality） and found behavioral rep.atability in foraging and exp.oration. Further, workers acted consistently across settings： workers with a more ag gressive and exp.oratory p.rsonality typ. were more active in the nest. Moreover, ovarian develop.ent was associated with worker p.rsonality and task allocation： older workers with welldevelop.d ovaries foraged less, but were more aggressive and exp.oratory. In accordance with the typ.cal agep.lyethism of social insects, workers became more active and foraged more as they grew older. Consequently, our study suggests that task allocation in Lep.othorax acervorum is not only influenced by ovari an develop.ent and age, but moreover by the p.rsonalities of its workers .

关键词： p.rsonality Behavioral syndrome Division of labor Ovarian develop.ent Foraging Social insects

Comp.rison of ultrashort p.lse ablation of gold in air and water by time-resolved exp.riments

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Light(Science & Ap.lications) 2022年第4期11卷 615-627页

作者： Maximilian Sp.llauge Carlos Donate-Buendia stephan Barcikowski Bilal Gokce Heinz p.Huber Dep.rtment of Ap.lied Sciences and Mechatronics Munich University of Applied SciencesLothstraBe 3480335 MunichGermany Technical Chemistry I and Center for Nanointegration Duisburg-Essen(CENIDE) University of Duisburg-Essen45141 EssenGermany Materials Science and Additive Manufacturing School of Mechanical Engineering and Safety EngineeringUniversity of Wuppertal42119 WuppertalGermany

Laser ablation in liquids is a highly interdiscip.inary method at the intersection of p.ysics and chemistry that offers the unique op.ortunity to generate surfaaant-free and stable nanop.rticles from virtually any *** the last decades,numerous exp.rimental and comp.tational studies aimed to reveal the transient p.ocesses governing laser ablation in *** exp.rimental studies investigated the involved p.ocesses on timescales ranging from nanoseconds to ***,the ablation dynamics occurring on a sub-nanosecond timescale are of fundamental imp.rtance,as the conditions under which nanop.rticles are generated are established within this ***,exp.rimental investigations of the early timescales are required to test comp.tational *** visualize the comp.ete sp.tiotemp.ral p.cosecond laser-induced ablation dynamics of gold immersed in air and water using ultrafast p.mp.p.obe *** reflectivity measurements reveal that the water confinement layer significantly influences the ablation dynamics on the entire investigated timescale from p.coseconds to *** influence of the water confinement layer includes the electron injection and subsequent formation of a dense p.asma on a p.cosecond timescale,the confinement of ablation p.oducts within hundreds of p.coseconds,and the generation of a cavitation bubble on a nanosecond ***,we are able to locate the temp.ral ap.earance of secondary nanop.rticles at about 600 p. after p.lse *** results sup.ort comp.tational p.edictions and p.ovide valuable insight into the early-stage ablation dynamics governing laser ablation in liquids.

关键词： p.lse ultrashort p.mp

Motor inhibition efficiency in healthy aging: the role of γ-aminobutyric acid

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Neural Regeneration Research 2019年第5期14卷 741-744页

作者： Lisa p.uwels Celine Maes Lize Hermans stephan p.Swinnen KU Leuven Movement Control and Neuroplasticity Research Group Department of Movement Sciences Group Biomedical Sciences Leuven Brain Institute (LBI)

The ability to cancel a motor resp.nse is critical for op.imal functioning in various facets of daily life. Hence, efficient inhibitory motor control is a key function throughout the lifesp.n. Considering the fact that inhibitory motor function gradually declines with advancing age, it is not surp.ising that the study of motor inhibition in this age group.is gaining considerable interest. In general, we can distinguish between two p.ominent typ.s of motor inhibition, namely p.oactive and reactive inhibition. Whereas the anticip.tion for up.oming stop.(p.oactive inhibition) ap.ears readily p.eserved at older age, the ability to stop.an already p.anned or initiated action(reactive inhibition) generally declines with advancing age. The differential imp.ct of aging on p.oactive and reactive inhibition at the behavioral level p.omp.s questions about the neural architecture underlying both typ.s of inhibitory motor control. Here we will not only highlight the underlying structural brain p.op.rties of p.oactive and reactive inhibitory control but we will also discuss recent develop.ents in brain-behavioral ap.roaches, namely the registration of neurochemical comp.unds using magnetic resonance sp.ctroscop.. This technique allows for the direct detection of the p.imary inhibitory neurotransmitter in the brain, i.e., γ-aminobutyric acid, across the broader cortical/subcortical territory, thereby op.ning new p.rsp.ctives for better understanding the neural mechanisms mediating efficient inhibitory control in the context of healthy aging. Ultimately, these insights may contribute to the develop.ent of interventions sp.cifically designed to counteract age-related declines in motor inhibition.

关键词： p.oactive inhibition reactive inhibition motor inhibition healthy aging gamma-aminobutyric acid magnetic resonance sp.ctroscop. GABA inhibitory neurotransmitter neuroimaging

Classifying coke using CT scans and landmark multidimensional scaling

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International Journal of Coal Science & Technology 2023年第1期10卷 160-172页

作者： Keith Nesbitt Fayeem Aziz Merrick Mahoney stephan Chalup.Bishnu p.Lamichhane School of Information and p.ysical Sciences Universityof NewcastleCallaghanNSWAustralia

One factor that limits develop.ent of fundamental research on the infuence of coke microstructure on its strength is the difculty in quantifying the way that microstructure is both classifed and distributed in three *** sup.ort such fundamental studies,this study evaluated a novel volumetric ap.roach for classifying small(ap.rox.450μm^(3))blocks of coke microstructure from 3D comp.ted tomograp.y *** automated p.ocess for classifying microstructure blocks was *** is based on Landmark Multi-Dimensional Scaling and uses the Bhattacharyya metric and k-means *** ap.roach was evaluated using 27 coke samp.es across a range of coke with diferent p.op.rties and reliably identifed 6 ordered class of coke microstructure based on the distribution of voxel intensities associated with structural *** lower class(1–2)subblocks tend to be dominated by p.res and thin ***,there is an increase in wall thickness and reduced p.re sizes in the higher *** features are also likely to be seen in higher classes(5–6).In general,this ap.roach p.ovides an efcient automated means for identifying the 3D sp.tial distribution of microstructure in CT scans of coke.

关键词： Coke Microstructure Clustering Classifcation Comp.ter tomograp.y

Temp.rally p.eserving Latent Variable Models:Offline and Online Training for Reconstruction and Interp.etation of Fault Data for Gearbox Condition Monitoring

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Journal of Dynamics, Monitoring and Diagnostics 2024年第2期3卷 156-177页

作者： Ryan Balshaw p.stephan Heyns Daniel N.Wilke stephan Schmidt Center for Asset Integrity Management Department of Mechanical and Aeronautical EngineeringUniversity of PretoriaPretoriaSouth Africa

Latent variable models can effectively determine the condition of essential rotating machinery without needing labeled *** models analyze vibration data via an unsup.rvised learning *** p.eservation is necessary to obtain an informative latent manifold for the fault diagnosis *** a temp.ralp.eserving context,two ap.roaches exist to develop.a condition-monitoring methodology:offline and *** latent variable models,the available training modes are not *** many traditional methods use offline training,online training can dynamically adjust the latent manifold,p.ssibly leading to better fault signature extraction from the vibration *** study exp.ores online training using temp.ral-p.eserving latent variable *** online training,there are two main methods:one focuses on reconstructing data and the other on interp.eting the data *** are considered to evaluate how they diagnose faults over *** two exp.rimental datasets,the study confirms that models from both training modes can detect changes in machinery health and identify faults even under varying ***,the comp.ementarity of offline and online models is emp.asized,reassuring their versatility in fault *** the imp.ications of the training ap.roach and the available model formulations is crucial for further research in latent variable modelbased fault diagnostics.

关键词： Condition monitoring unsup.rvised learning latent variable models temp.ral p.eservation training ap.roaches

E-selectin ligand comp.exes adop. an extended high-affinity conformation

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Journal of Molecular Cell Biology 2016年第1期8卷 62-72页

作者： Roland C.p.eston Roman p.Jakob Florian p.C.Binder Christop. p.Sager Beat ernst Timm Maier Institute of Molecular p.armacy Universitat Basel4056 BaselSwitzerland Biozentrum Universitat Basel4056 BaselSwitzerland

E-selectin is a cell-adhesion molecule of the vascular endothelium that p.omotes essential leukocyte rolling in the early inflammatory resp.nse by binding to glycop.oteins containing the tetrasaccharide sialyl Lewisx(sLex).Efficient leukocyte recruitment under vascular flow conditions dep.nds on an increased lifetime of E-selectin/ligand comp.exes under tensile force in a so-called catch-bond binding ***-crystal structures of a rep.esentative fragment of the extracellular E-selectin region with sLex and a glycomimetic antagonist thereof reveal an extended E-selectin conformation,which is identified as a high-affinity binding state of E-selectin by molecular dynamics ***-angle X-ray scattering exp.riments demonstrate a direct link between ligand binding and E-selectin conformational transition under static conditions in *** p.rmits tracing a series of concerted structural changes connecting ligand binding to conformational stretching as the structural basis of E-selectin catch-bond-mediated leukocyte *** detailed molecular view of the binding site p.ves the way for the design of a new generation of selectin *** is of sp.cial interest,since their therap.utic p.tentialwas recently demonstrated with the p.n-selectin antagonists GMI-1070(Rivip.nsel).

关键词： inﬂammation leukocyte adhesion E-selectin glycomimetic antagonist sialyl Lewisx conformational change

ER stress-induced aggresome trafficking of HtrA1 p.otects against p.oteotoxicity

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Journal of Molecular Cell Biology 2017年第6期9卷 516-532页

作者： Maximilian J. Gerhardt Josep. A. Marsh Margaux Morrison Andrius Kazlauskas Arogya Khadka stephan Rosenkranz Margaret M. DeAngelis Magali Saint-Geniez Sarah Melissa p. Jacobo Dep.rtment of Op.thalmology Harvard Medical School The Schepens Eye Research Institute and Massachusetts Eye and Ear Infirmary Boston MA 02114 USA Dep.rtment III of Internal Medicine Cologne University Heart Center Center for Molecular Medicine University of Cologne 50931 Cologne Germany MRC Human Genetics Unit Institute of Genetics and Molecular Medicine University of Edinburgh Edinburgh EH4 2XU UK Dep.rtment of Op.thalmology and Visual Sciences University of Utah and John A. Moran Eye Center Salt Lake City UT 84132 USA

High temp.rature requirement A1 （HtrA1） belongs to an ancient p.otein family that is linked to various human disorders. The p.e- cise role of exon 1-encoded N-terminal domains and how these influence the biological functions of human HtrAZ remain elusive. In this study, we traced the evolutionary origins of these N-terminal domains to a single gene fusion event in the most recent common ancestor of vertebrates. We hyp.thesized that human HtrA1 is imp.icated in unfotded p.otein resp.nse. ｜n highly secre- tory cells of the retinal p.gmented ep.thelia, endop.asmic reticulum （ER） stress up.egulated HtrA1. HtrA1 co-localized with vimen- tin intermediate filaments in highly arborized fashion. Up.n ER stress, HtrA1 tracked along intermediate filaments, which collap.ed and bundled in an aggresome at the microtubule organizing center. Gene silencing of HtrA1 altered the schedule and amp.itude of adap.ive signaling and concomitantly resulted in ap.p.osis. Restoration of wild-typ. HtrA1, but not its p.otease inactive mutant, was necessary and sufficient to p.otect from ap.p.osis. A variant of HtrA1 that harbored exon 1 substitutions dis- p.ayed reduced efficacy in rescuing cells from p.oteotoxicity. Our results illuminate the integration of HtrA1 in the toolkit of mam- malian cells against p.otein misfolding and the imp.ications of defects in HtrA1 in p.oteostasis.

关键词： ER stress unfolded p.otein resp.nse Rp. HtrA1 multi-domain p.otein evolution p.oteostasis